To liberate hydrocarbons (e.g., oil, gas, etc.) from a subterranean formation, wellbores may be drilled that penetrate hydrocarbon-containing portions of the subterranean formation. The portion of the subterranean formation from which hydrocarbons may be produced is commonly referred to as a “production zone.” In some instances, a subterranean formation penetrated by the wellbore may have multiple production zones at various locations along the wellbore.
Generally, after a wellbore has been drilled to a desired depth, completion operations are performed. Such completion operations may include inserting a liner or casing into the wellbore and, at times, cementing a casing or liner into place. Once the wellbore is completed as desired (lined, cased, open hole, or any other known completion) a stimulation operation may be performed to enhance hydrocarbon production into the wellbore. Examples of some common stimulation operations involve hydraulic fracturing, acidizing, fracture acidizing, and hydra-jetting. Stimulation operations are intended to increase the flow of hydrocarbons from the subterranean formation surrounding the wellbore into the wellbore itself so that the hydrocarbons may then be produced up to the wellhead.
Hydraulic fracturing specifically is often utilized to stimulate the production of hydrocarbons from subterranean formations penetrated by wellbores. In performing hydraulic fracturing treatments, a production zone or portion of a formation to be fractured is isolated using conventional packers or the like, and a fracturing fluid is pumped through the wellbore into the isolated portion of the formation to be stimulated at a rate and pressure such that fractures are formed and extended into the formation. Propping agents, or “proppants,” function to prevent the fractures from closing and thereby provide conductive channels in the formation through which fluids can readily flow to the wellbore.
In wells penetrating very low to medium permeability formations, and/or wells not producing to expectations, it is often desirable to create fractures in the formations near the wellbores in order to improve hydrocarbon production from the formations. Furthermore, in some wells, it is desirable to individually and selectively create multiple fractures having adequate conductivity, usually at predefined distances apart along the wellbore, so that as much of the hydrocarbons in an oil and gas reservoir as possible can be drained/produced into the wellbore. When stimulating a reservoir from a wellbore, especially those that are highly deviated or horizontal, to create multizone fractures along the wellbore, it may be necessary to cement a liner, or casing, to the wellbore and mechanically isolate the zone being fractured from other previously fractured zones or zones to be subsequently fractured.
In order to create such fractures in formations penetrated by cased or uncased wellbores, a jetting apparatus can be used wherein the jetting apparatus is equipped with jetting nozzles which expel high velocity fluids from the jetting apparatus toward the subterranean formation. Using this method, multiple fractures can be created one at a time or at the same time. To create the fractures, jetting nozzles are placed within the wellbore such that they are set at predetermined locations on the jetting apparatus to create fractures at defined locations or geometries relative to the wellbore.
It should be understood that the various aspects are not limited to the arrangements and instrumentality shown in the drawings.